U.S. Pat. No. 3,758,643 discloses blends of partially cured monoolefin rubber such as EPDM or EPM with a polyolefin resin (polypropylene) where the rubber phase was cured with a peroxide. The compositions were useful as thermoplastic elastomers.
U.S. Pat. No. 4,104,210 discloses compositions of blends of vulcanized high diene rubbers with crystalline thermoplastic polyolefin resins. The diene rubbers include copolymers of diene with styrene, vinyl pyridine, acrylonitrile or methacrylonitrile. The diene rubber content in the blends is about 75-55 parts by weight and the thermoplastic polyolefin content is 25-45 parts by weight and the diene was highly crosslinked. U.S. Pat. No. 4,104,210 does not disclose that useful blend compositions can be obtained when the diene copolymer rubber comprises of multiple arms and is coupled with tin or silicon, it also does not disclose that thermoplastic blend compositions that have improved processability in injection molding and extrusion can be developed with the tin or silicon-coupled diene copolymer rubbers and copolymer rubbers that are highly branched. The subject patent also does not suggest that the diene-based rubbers used in the blends may comprise of copolymers of 1,3diene polybutadiene and isoprene.
U.S. Pat. No. 4,130,535 discloses blends of polyolefin resins and completely cured monoolefin copolymer rubber such as Ethylene-Propylene-Diene rubber.
U.S. Pat. No. 4,183,876 discloses thermoplastic compositions of crystalline thermoplastic polyolefin resins and cross-linked polyalkenamer rubber.
U.S. Pat. No. 4,202,801 discloses dynamically and partially cured blends of monoolefin copolymer rubbers such as ethylene-propylene copolymer rubbers or ethylene-propylene-diene terpolymer rubbers, polyolefin resin, and conjugated diene rubbers such as cis-1,4 polyisoprene or cis-polybutadiene or polychloroprene.
U.S. Pat. No. 4,203,884 discloses blends of polynorborene, plasticizer, and thermoplastic polyolefin resin.
U.S. Pat. No. 4,250,273 discloses thermoplastic ter-blend compositions comprising of about 10 to 50 parts of a crystalline 1-olefin polymer, about 80 to 15 parts of a random styrene-butadiene rubber copolymer and from about 5 to 55 parts of a highly saturated elastomer. The invention also related to ter-blends where the rubbers are partially vulcanized. U.S. Pat. No. 4,250,273 does not disclose that useful blend compositions can be obtained when the diene copolymer rubber comprises of multiple arms and is coupled with tin or silicon, it also does not disclose that high impact blend compositions can be developed with the tin or silicon-coupled diene copolymer rubbers Further, it does not suggest that a binary blend composition of a styrene-butadiene copolymer rubber and a thermoplastic olefin resin can be used to make useful compositions with good surface appearance and physical properties.
U.S. Pat. No. 4,311,628 relates to blends of polypropylene and EPDM where EPDM was cured with phenolic resins for better oil resistance.
U.S. Pat. No. 4,271,049 discloses blends of crystalline polypropylene and cured rubbers including styrene-butadiene rubber up to 25 weight % styrene or alpha-methyl styrene and the rubber is cured with phenolic or urethane or sulfur donor curative. The preferred compositions were from 25-75 parts of polypropylene and about 75-25 parts of rubber. Furthermore, U.S. Pat. No. 4,271,049 does not teach that useful blend compositions can be obtained when SBR rubber comprises of multiple arms and is coupled with tin or silicon, it also does not disclose that high impact blend compositions can be developed with the tin or silicon-coupled diene copolymer rubbers.
U.S. Pat. No. 4,183,876 teaches blends of crosslinked polyalkenamer rubber and crystalline thermoplastic blends.
U.S. Pat. No. 4,340,684 is similar to U.S. Pat. No. 4,250,273 and further teaches partial curing of the rubber and narrows the claims for the melt flow rate of the formed blend. The Styrene content in the SBR rubber is up to 40% by weight of the said rubber. U.S. Pat. No. 4,340,684 does not disclose that useful blend compositions can be obtained when the diene copolymer rubber comprises of multiple arms and is coupled with tin or silicon, it also does not disclose that that compositions that have improved processability in injection molding and extrusion can be developed with the tin or silicon-coupled diene copolymer rubbers. Further, it does not suggest that a binary blend composition of a styrene-butadiene copolymer rubber and a thermoplastic olefin resin can be used to make useful compositions with good surface appearance and physical properties.
U.S. Pat. No. 4,343,918 claims processes for making blends primarily disclosed in U.S. Pat. No. 4,250,273.
U.S. Pat. No. 4,594,390 discloses a process for preparation of thermoplastic elastomers of polypropylene and EPDM under conditions of high shear required for dynamic vulcanization of the EPDM.
U.S. Pat. No. 4,927882 discloses thermoplastic elastomer produced by dynamic vulcanization of SBR to form a dispersed phase of crosslinked SBR in a co-continuos phase of SEBS and polypropylene. The blends were useful in pharmaceutical, consumer and health industries.
U.S. Pat. No. 5,021,500 teaches TPO compositions prepared with a crystalline thermoplastic resin and a halobutyl rubber.
U.S. Pat. No. 5,051,478 provides a dynamically vulcanized composition comprising of a polyolefin resin, an elastomer, and an ethylene copolymer resin such as a copolymer of ethylene and vinyl acetate or an alkyl acrylate.
U.S. Pat. No. 5,248,729 suggests the process for making thermoplastic composition by heat treating a mixture of a thermoplastic resin with no olefinic unsaturated carbon-carbon bond, an elastomer from the group of SBS, SIS, 1,2-polybutadiene rubber, and EPDM rubber, with a crosslinking agent of dihydroaromatic compound.
U.S. Pat. No. 5,523,356 teaches blends obtained by dynamic vulcanization of polypropylene, polyisobutene, EPDM rubber, and polybutadiene.
U.S. Pat. No. 5,621,045 discloses thermoplastic vulcanizates from semi-crystalline polyolefins and blends of crosslinked rubbers with one rubber being C4 to C7 isomonoolefin based (isobutylene) and rubber being EPDM or rubbers derived from a conjugated diene.
U.S. Pat. No. 6,051,681 discloses process for preparation of thermoplastic elastomer with a rubber such as ethylene-alpha-olefin diene terpolymer (EPDM) and a thermoplastic resin, phenolic curative, a hydrotalcite and a HALS compound.
U.S. Pat. No. 6,207,761 discloses thermoplastic ionomer blend or alloy composition containing an ionomer, crosslinked rubber and polyolefin resins.
The subject invention discloses thermoplastic composition which is comprised of a blend of a thermoplastic polyolefin resin and a modified elastomer, wherein said thermoplastic polyolefin resin selected at least from the group of polyethylene, isotactic polypropylene, syndiotactic polypropylene, polypropylene impact copolymers containing about 1-7% by weight of ethylene, butene, hexene, or octene, polyolefin copolymers such as ethylene-butene, hexene, or octene, polybutene, reactor grade modified polypropylene, metallocene polypropylene, oxypolyolefin, wherein said modified elastomer is comprised of a conjugated diene selected from 1,3-butadiene and isoprene, wherein said modified elastomer is highly branched, wherein said modified elastomer is characterized by having a Gxe2x80x2 and Gxe2x80x3 frequency crossover of no more than 4 radians/s at 100xc2x0 C., wherein the thermoplastic polyolefin is present in an amount which is within the range of about 5 parts by weight to about 95 parts by weight, and wherein the modified elastomer is present in an amount which is within the range of about 5 parts by weight to about 95 parts by weight, based upon the total weight of the thermoplastic composition. Oxypolyolefins are polyolefins that typically contain less than 1% repeat units of the -O-(CH2)n- structure.
The present invention also discloses a process for preparing a thermoplastic composition which comprised (1) mixing a thermoplastic polyolefin resin and a modified elastomer at a temperature about or above the melting point of the thermoplastic resin in a mixing devise, (2) discharging the mixed blend from the mixing devise, and (3) forming the mixed blend into a pellet, sheet, or article of manufacture, wherein said thermoplastic polyolefin resin selected at least from the group of polyethylene, isotactic polypropylene, syndiotactic polypropylene, polypropylene impact copolymers containing about 1-7% by weight of ethylene, butene, hexene, or octene, polyolefin copolymers such as ethylene-butene, hexene, or octene, polybutene, reactor grade modified polypropylene, metallocene polypropylene, oxypolyolefin, wherein said modified elastomer is comprised of a conjugated diene selected from 1,3-butadiene and isoprene, wherein said modified elastomer is highly branched, wherein said modified elastomer is characterized by having a Gxe2x80x2 and Gxe2x80x3 frequency crossover of no more than 4 radians/s at 100xc2x0 C., wherein the thermoplastic polyolefin is present in an amount which is within the range of about 5 parts by weight to about 95 parts by weight, and wherein the modified elastomer is present in an amount which is within the range of about 5 parts by weight to about 95 parts by weight, based upon the total weight of the thermoplastic composition.
The thermoplastic compositions of this invention are particularly useful for manufacturing automotive interior panels, automotive exterior body panels, automotive instrument panels, soft-touch parts, household appliances, household goods, toys, razor holders, razor handles, stapler handles, pen grips, computer housings, and computer key boards.